The goal of the proposed research is to design and synthesize cyclic sulfur-containing compounds that will be chelating agents for lead and mercury ions. By model-building in a computer, derivatives of the enniatin antibiotics, of the "crown ethers" and of cyclohexaamylose will be examined for their ability to provide the geometry required of a lead and/or mercury chelator. The most promising compounds will be synthesized and tested for their ability to chelate lead and mercury and to remove these ions from biological tissues. BIBLIOGRAPHIC REFERENCES: "Selective Reduction of the Amide Carbonyl Group in Dipeptides by Borane". Roeske, Weitl, Prasad and Thompson, J. Org. Chem. 41, 1260 (1976). "Reaction of Potassium Salts of Boc Amino Acids with Chloromethyl Polystyrene Catalyzed by 18-Crown-6". Roeske and Gesellchen, Tetrahedron Letters, Sept. 1976, in press.